Reasons for bitter spring season weather
April 28, 2011
Announcing that it’s been cold is nothing to stop the presses for, but I’ll announce it anyway. It has been cold. Not complaining; just stating facts. I scold those who whine about things out of their control, so I’m not complaining. Still, it has been cold. And wet. And windy. It’s been cold, wet, windy and miserable. Not complaining, just stating facts.
La Niña, we are told, has been the cause of the Super-winter. It occurs when the tropical Pacific Ocean is cooler than normal. The temperature change is subtle. Extreme years see a cooling of six to seven degrees Fahrenheit. According to the National Oceanic and Atmospheric Administration, in most La Niña years the cooling is two to four degrees. Since last October the tropical regions of the Pacific have been about three degrees below normal.
Despite the fact that you probably wouldn’t even notice the temperature change if you were lucky enough to be snorkeling in Fiji, it manages to impact our weather. The cool water below cools the air above. Because the cooler air is inherently denser, it causes one of those interesting weather terms: a massive high-pressure ridge. This is where the jet stream gets involved. The high-level winds we know as the jet stream are forced to flow up and around the high-pressure area over the Gulf of Alaska, then down through Canada and finally over the Midwest and on to the East coast. When we’re getting our weather from Alaska it becomes obvious as to why it has been so cold so long. It’s the classic Alberta clipper on a much larger scale.
A normal winter jet stream flows from the tropical Pacific and hits land over California or Oregon and brings us milder, more stable weather. During La Niña winters, such as the one we are trying to get out of, we are right on the battle-front between the warm and moist and cold and stuffy, causing lots of snow and a back-and-forth spring.
I know it won’t cause the clouds to break or the wind to warm, but hopefully thinking about why the weather is the way it is can give us some perspective and stop the constant griping. Hell, who am I kidding? It plain sucks.